It is known to acoustically eject a droplet containing an analyte from a fluid sample and transport the droplet into an interface of a mass spectrometer. An analyte solution may be placed onto a piezoelectric transducer and ultrasound may be applied to produce a single drop that is then transferred into the inlet of a mass spectrometer.
US2004/0118953 (Elrod) discloses a high throughput method and apparatus for introducing biological samples into analytical instruments.
US2012/0145890 (University of Glasgow) discloses methods and systems of mass spectrometry.
US2002/0109084 (Ellson) discloses acoustic sample introduction for mass spectrometric analysis.
US2005/0054208 (Fedorov) discloses electrospray systems and methods.
WO2011/060369 (Goodlett) discloses generating ions using a surface acoustic wave device, and detecting these by mass spectrometry.
US2014/0072476 (Otsuka) discloses an ionisation device, a mass spectrometer using the ionisation device and an image generation system.
It is desired to improve ionisation techniques involving the application of ultrasound to a sample.